This invention relates to the art of molten metal carrying ladle cars and, more particularly, to an improved closure member for closing the opening in the car between pouring and subsequent refilling operations.
It is of course well known that ladle cars, sometimes referred to as torpedo cars because of their shape, are employed for carrying molten metal from one location to another such as, for example, from a blast furnace location to a basic oxygen furnace location in a steel mill operation. As is further well known, such ladle cars include a container mounted on a wheeled frame structure for rotation relative thereto about a horizontal axis and which container includes an opening radially thereinto and through which molten metal is adapted to be poured into and from the container. More particularly in this respect, rotation of the container provides for the opening to be positioned vertically upwardly to facilitate pouring molten metal into the container and, thereafter, to be rotated in either direction about the horizontal axis to displace the opening outwardly and downwardly from the vertical position to facilitate pouring of the molten metal from the container. The supporting framework is mounted on wheels to enable transporting the car between the pouring and filling locations and, often, several cars are connected together to form a train.
Following the pouring of molten metal from a ladle car, it is desirable to retain the temperature within the container as high as possible during the period between pouring and the subsequent refilling of the container. Such temperature retention is desired so as to minimize the molten metal temperature loss during the period between refilling and the next pouring operation and which temperature loss results in part from the temperature drop in the container prior to refilling. Generally, there can be as much as a three to ten hour delay between pouring and refilling the ladle car. This delay can result in a loss of several hundred degrees of heat in the container piror to refilling and, thus, an undesirable reduction in the molten metal temperature between such refilling and the next pouring operation.
Efforts heretofore to minimize such heat loss during the period between pouring and refilling have included covering the ladle car container opening with a blanket of fibrous insulating material which is secured to circumferentially opposite sides of the container through the use of strapping arrangements. While such a blanket arrangement serves to reduce the loss, there are several disadvantages attendant to the use thereof. Among these disadvantages is the fact that the physical condition of the outer end of the opening into the container most often precludes an interengaging relationship between the blanket and opening to promote minimizing heat loss. In this respect, slag build up and/or erosion about the outer peripheral edge of the container opening, which results from pouring and filling operations, produces an irregular outer surface contour across which the blanket extends. Such irregularities promote leakage paths between the container opening and blanket and through which a considerable amount of heat can be lost during the period between pouring and refilling. Furthermore, the placing of such a blanket across the opening requires the use of a crane or the like to drop the blanket into position, and one or more men on the ground next to the car to achieve fastening of the blanket straps to the container. Accordingly, it will be appreciated that such a procedure is both time consuming and potentially hazardous to the workmen on the ground. As an alternative to the use of an overhead crane to initially position the blanket on the container, the blanket can be strapped to one side and the container rotated in the direction to displace the container opening toward the ground on the same side of the car, after which workmen on the latter side and through the use of rods or the like push the blanket across the opening so that strapping of the blanket to the opposite side of the container can be achieved by rotating the container opening back to the upper position thereof. Such an alternative procedure is not only time consuming but extremely hazardous to workmen in that the ladle car containers are never completely emptied, whereby the initial rotation of the container to displace the opening downwardly subjects the workmen to potential injury through the displacement of hot slag outwardly through the container opening.
In the refilling process with regard to ladle cars having such blankets of insulating material covering the container opening, the cover is not removed and the molten metal is poured into the container through the cover. Nonremoval of the cover is preferred in order to optimize heat retention in the container prior to refilling thereof, but a blanket type cover masks the location of the opening into the container. Therefore, refilling is either accompanied by guess work with respect to the appropriate positional relationship between the container opening and the stream of molten metal, which obviously can be extremely hazardous, or requires a workman to punch a hole or holes through the blanket to determine the location of the container opening thus to enable appropriate positioning of the car for refilling. Furthermore, since the insulating blankets are not removed it will be appreciated that several uses of the ladle car results in a build up of blanket material and straps, which build up can further increase heat losses by establishing heat loss paths between the outermost blanket and portions of the previously used blankets therebeneath. Still further, such a build up of blanket material must ultimately be removed from the ladle car, and this is a time consuming procedure during which there is an undesirable heat loss from the container.